Re: [PATCH 4/6] signal: sigprocmask() should do retarget_shared_pending()

From: Linus Torvalds
Date: Thu Apr 14 2011 - 16:34:12 EST


On Thu, Apr 14, 2011 at 1:10 PM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
>
> Well, I don't know the common definition... But please note that
> signandsets() does ((x) & ~(y)), so I defined nor as (x | ~y) by analogy.

Yeah, "nand" is really "not and" (ie "~((x)&(y))").

The expression ((x) & ~(y)) should typically be called "andn" (see for
example the x86 instruction set "pandn" and "andnpd" or whatever they
are called for sse instructions).

And "nor" really should be "~(x|y)". You want the "orn" combination
(and the famously hard-to-google "porn" instruction for the vectorized
version)

Linus
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